【作者】 孙永根； 杜之明； 苏艳妮；

【Author】 Sun Yong-gen;Du Zhi-ming;Su Yan-ni;Harbin Institute of Technology;

【机构】 哈尔滨工业大学；

【摘要】 针对目前用于液态模锻成形的高强韧铝合金热裂倾向严重的缺陷,通过优化合金成分、设计熔炼获得热裂性倾向较低的Al-5Cu-4.5Mg-2.5Zn合金。利用制备的Al-5Cu-4.5Mg-2.5Zn合金进行液态模锻成形,对成形件的微观组织及性能进行研究。分析可知Al-5Cu-4.5Mg-2.5Zn合金中除基体外共有三种第二相存在,在晶界上呈鱼骨状分布的粗大共晶组织S（Al₂CuMg）相;少量沿晶界分布的块状和在晶粒内沿位错线弥散分布的条状θ（Al₂Cu）相,其与基体保持共格关系;弥散分布晶内的η（MgZn₂）相。固溶强化与共晶组织共同影响着合金性能,使得Al-5Cu-4.5Mg-2.5Zn合金热裂倾向低、综合性能优异:HCS=40、σb=327MPa、δ=2.7%、HB=107N/mm²。更多还原

【Abstract】 According the serious hot cracking defects of high strength aluminum alloy used in liquid forging, Al-5Cu-4.5Mg-2.5Zn alloy with low hot cracking tendency was prepared by optimizing and designing alloy compositions. The microstructures and properties of forming parts obtained by liquid forging were analyzed and discussed. The results show that there are three types of second phases in Al-5 Cu-4.5 Mg-2.5 Zn alloy. They are the coarse eutectic structures, S（Al₂CuMg） phases, in the crystal boundary, a little amount of θ（Al₂Cu） phases in a coherent relation with the matrix, some of which are blocky-shaped along the boundaries and some of which are strip-shaped and dispersedly distributed along the dislocation line, and a little of η（MgZn₂） phases dispersedly distributed in the grains. The combination of solid solution strengthening and eutectic structures affects the properties of Al-5 Cu-4.5 Mg-2.5 Zn alloy, which makes the hot cracking tendency low and comprehensive performances excellent: HCS=40, σb=327 MPa, δ=2.7%, HB=107 N/mm².更多还原